There have been studied wireless communication standards using the same frequency band as a television broadcast being a licensed business but can be operated without such a license. In these standards, a television broadcaster is a primary user, and only when the licensed frequency band of the primary user is not used, a secondary user is allowed to operate wireless communication in this frequency band (unused licensed frequency band=white space).
A communication device of the secondary user used under such an environment makes an inquiry about TV channels to, for example, a dedicated database so as to confirm that no TV signal exists. Specifically, current positional information of the communication device is sent to the database, and a list of usable (effective) frequency bands at this position is obtained from the database. Then, a frequency band to be used is selected from among the frequency bands in the list, and an operation of wireless communication as the secondary user is carried out.
As a mode of frequency band use by such a secondary user, it is conceivable that the communication is performed over a broadband by simultaneously using a plurality of frequency bands (channels) which are consecutive. By this mode, great advantages can be obtained such as performing a communication that is faster or has a very low error rate by giving redundancy. Specifications required by individual communications vary, and thus if such an application is possible, the utility value as a communication system increases.
On the other hand, when such an operation is considered, it is possible that problems occur in securing a plurality of frequency bands consecutive. Specifically, it is highly possible that many of the individual communications are a communication which only needs a single frequency band, and if frequency bands are allocated for these communications without planning, probability that a plurality of necessary frequency bands consecutive can be secured between allocated frequency bands becomes low. That is, it is possible that the lineup of available frequency bands fragments disorderly.